A rocket engine provides propulsion to a craft by combusting propellants, such as fuel and an oxidizer, at high pressure. The combustion of the fuel and the oxidizers provide a hot gas which is then expelled through a nozzle at high velocity providing the thrust. Generally, these systems include high pressure and high temperature components which, due to the high pressure and high temperature environments, may be highly complex, heavy, and expensive.
Generally, turbines provide power to pumps which pump fuel and the oxidizer to the main combustion chamber of a rocket engine. High pressure gases power the turbines, which in turn power the pumps to feed the propellants. In order to produce high pressure gases, combustion devices such as pre-burners are provided to initially heat or combust a portion of the propellants. Certain propellants which may cool the main combustion chamber transfer the high pressure and high temperature gases therefrom to power the turbo pumps. This, however, requires an additional supply of propellants to power the turbines and cool the combustion chamber.
Regardless, it is generally known to power the turbines with high pressure and high temperature gases. As such, the turbines themselves must withstand high pressures and temperatures to perform properly in these environments. Additionally, several seals must be used to ensure that the oxidizers and fuels do not mix before entering the main combustion chamber. As such a pre-mixture may produce a system failure. Generally, the seals are purged with an inert or tertiary purge gas which is consumed in the seal to ensure that the oxidizer and fuel do not mix.